A piece of flint struck from a core which characteristically shows traces of the processes of removal: concentric fracture ripples and a bulb of percussion. Flakes with a length:breadth ratio of 2:1 or more are usually referred to as blades. In some cases flakes are the result of shaping a block of flint into a tool of some kind. When removed from a prepared core, however, they were usually used as blanks for making tools. Primary flakes (also called decortication flakes) are large, thick flakes struck off a nodule when removing the cortex and preparing it for working. Secondary flakes (also called reduction flakes) are large flakes struck off a piece to reduce its size or thickness. Tertiary flakes are small flakes struck off when shaping the detail of a piece to make a specific tool. Retouching flakes are tiny, extremely thin flakes pinched or pushed off a piece to finish it, to fine‐shape part of the surface, sharpen it, or resharpen it. Notching flakes are produced when putting hafting notches in stone tools. See also percussion flaking; pressure flaking.